Spinal tuberculosis
Incidence
Until recent AIDS epidemic a rare disease in the first world
M > F
Most common level L1
Aetiology
Mycobacterium tuberculosis
Pathology
Usually a secondary infection - primary lesion in lung, GIT or GUT
Rarely spine involved in direct spread from other structures
The infection begins in the paradiscal vertebra.
Infection tends to spread across the periphery of the disc - to involve the metaphyses of the vertebrae above and below.
It is typical to see more than one vertebra involved.
The ant and post longitudinal ligs and periosteum are stripped up, arteries thrombose and bone dies as well being directly destroyed by the granulomatous process
The disc, being relatively avascular is relatively spared and destroyed late in the disease
Thus progression: granuloma formation
pus production +/- abscess formation
bone loss, death +/- collapse
neuro involvement may be seen in active or healed disease
Active disease à pressure from pus, granuloma, bony sequestra, disc material, bony collapse
Can get TB meningitis or meningomyelitis
Healed disease à due to internal bony bridge or fibrous tissue constriction
Clinically
Depends on stage of disease
General -fever, malaise, weight loss
Evidence of TB elsewhere
Local --rest pain, worse with motion ,muscle spasm, deformity, sinus
Neurological -“Pott’s Paraplegia”
Deformity progression occurs in two distinct phases
Phase I - changes in the active phase
Phase II - changes after the disease is cured
Investigation -
Bloods:
WCC, ESR, CRP
Mantoux:
Radiology:
CXR
Plain films
CT
MRI - sensitivity of 100% and specificity of 88%
Biopsy: Z-N staining of material high yield in active disease, poorer in healed disease
Diagnosis
Combination of the above
DDx other infection, neoplasia
Healed TB can resemble congenital fusions
Treatment
Medical
Triple therapy:
Streptomycin: initial 2-3 mths
Isoniazid: 9 mths
Rifampicin: 9 mths
Nonsurgical treatment alone -
Patients with early disease
Minimal bone involvement
Medical contraindications to operation
Therapeutically refractory cases of tuberculosis of the spine are increasing in association with the presence of HIV and multidrug-resistant tuberculosis.
Surgery
Kyphosis of 60 degrees or more, or one which is likely to progress
Anterior decompression, posterior shortening, posterior instrumented stabilisation and anterior and posterior bone grafting in the active stage of the disease
Internal kyphectomy (gibbectomy) - late onset paraplegia with severe healed kyphosis.
Advantages of surgery -
prevention of progression of abscess
relieve pressure on neural tissue
graft under compression - fusion almost sure- thus late kyphosis prevented
Complications
Neurological deficit - paraplegia/quadriplegia
Deformity
